1. Technical Field
The present invention relates to a shock measurement apparatus, and in particular to a shock measurement apparatus that can accurately detect and record shock received by a hard disk drive installed in a notebook personal computer (PC).
2. Description of the Related Art
Hard disk drives are the most popular data storage means for computers. A hard disk drive is composed of one or more magnetic disks arranged coaxially and driven by a spindle motor. Data is read/written by a magnetic head facing the magnetic disk and the magnetic disk is driven by an actuator, typically a voice coil motor. The magnetic disk, the magnetic head, and the actuator are enclosed in a housing called an enclosure case.
A hard disk drive is sensitive to shock because it includes dynamic mechanics, such as the spindle motor for rotating the magnetic disk and the actuator for the magnetic head. Moreover, a hard disk drive is often installed within a notebook PC that can experience shock events. For example, it can bump against obstacles while being carried or fall to the floor. Notebook PCs receive greater and more frequent shocks than desktop PCs. Accordingly, a hard disk drive installed in a notebook PC requires high shock-resistance.
Improving the shock-resistance of the hard disk drive requires that the shock that the hard disk receives be accurately measured. Several uses of such a measurement exist. For example, the shock received by a notebook PC during operation may be measured, and if the measured value exceeds a predetermined value, read/write operation of the hard disk drive can be suspended. Additionally, failure of the PC may be predicted based on measurements of the shock received by the notebook PC during operation.
In order to measure the shock accurately, the shock received by the hard disk drive must be measured while the hard disk drive is installed in the notebook PC. Unfortunately, attaching a shock measurement instrument to the hard disk drive or the notebook PC would change the size and center of mass of the system. These changes increase the difficulty of accurately measuring the shock received by a hard disk drive installed in a notebook PC.
Many instruments for measuring and recording shock received by equipment have been proposed, including those described in Published Unexamined Patent Application Nos. 2-179479, 4-152268, 5-133974, 2000-97730, 2000-97965, and 2000-99868.
For example, in Published Unexamined Patent Application No. 2-179479, a shock recording apparatus is disclosed which comprises means for detecting shock in X, Y, and Z directions, recording means for recording information about the shock, a battery for power supply, and a connector for providing the information recorded in the recording means to an external indicating or recording means, all contained in a small portable case.
In Published Unexamined Patent Application No. 5-133974, a hard disk drive is disclosed in which a sensor with piezoelectric polymer film is installed. Published Unexamined Patent Application No. 5-133974 discloses a shock apparatus which senses shock received by a hard disk drive and provides a write stop signal to the read/write head.
As mentioned above, many proposals have been made concerning apparatus for sensing and recording shock. However, they are inadequate for accurately measuring the shock received by a hard disk drive. That is, if the shock recording apparatus proposed in Published Unexamined Patent Application No. 2-179479 is attached to a notebook PC, the measured shock value would be inaccurate due to the altered weight and center of mass of the system.
In the process of developing a new note book PC, shock received by a hard disk drive attached to the PC may be measured, and the result of the measurement may be reflected in the design of the PC. The apparatus proposed in Published Unexamined Patent Application No. 5-133974 can measure shock without making substantial change to the physical characteristics of a notebook PC because it uses the shock sensor made of piezoelectric polymer film. However, that apparatus is designed to measure shock during operation. It provides a write stop signal to the read/write head after sensing shock received by the hard disk drive and does not accommodate measurement during development that can be reflected in the design of a new notebook PC.
It is therefore an object of the present invention to provide a shock measurement apparatus that can accurately measure shock received by equipment, such as a notebook PC, without altering the physical characteristics of the equipment. It is another object of the present invention to provide a shock measurement apparatus that allows the result of the shock measurement to be reflected in the design of new equipment.
The inventor conceived the idea of constructing a shock measurement apparatus with an enclosure similar to a hard disk drive in order to measure shock received by the hard disk drive of a notebook PC without altering the physical characteristics of the PC. The components, such as magnetic disks, of the hard disk drive are contained in a housing called an enclosure case and the size of the enclosure case is specified by a specification called a xe2x80x9cform factor.xe2x80x9d In current notebook PCs, a hard disk drive having a 2.5-inch form factor is used, and a region called a xe2x80x9cmedia bayxe2x80x9d (or device bay), intended for receiving the hard disk drive is provided in the body of the notebook PC. The hard disk drive is attached to this bay. Therefore, if a shock measurement apparatus is fabricated, which has an enclosure of the same size as the form factor of the hard disk drive and the same weight, shock measured with this shock measurement apparatus attached to the media bay of the notebook PC would imitatively measure shock actually received by the hard disk.
The current 2.5-inch form factor of the hard disk installed in notebook PCs typically has dimensions of 100 mm (l), 70 mm (w), and 9.5 mm (t). A major problem with fabricating the shock measurement apparatus using an enclosure of this size is that the thickness is limited to 9.5 mm. Great difficulty arises in finding a power supply battery that supplies power sufficient to drive the shock measurement apparatus and fits within this thickness range. The notebook PC; however, contains a battery for driving the PC, and the power problem can be solved by arranging the shock measurement apparatus so as to receive electric power from that battery. A connector compatible with a power connector for the hard disk drive is provided in the shock measurement apparatus of the present invention to allow the shock measurement apparatus to be supplied with power by the battery of the notebook PC.
The present invention takes account of the above-mentioned considerations and provides a shock measurement apparatus for measuring shock received by a hard disk drive device installed in a computer. The apparatus comprises: a sensor for detecting the shock, a power receiving connector for receiving power from the computer, and an enclosure containing the sensor and the power connector and having the same size as a disk drive device.
Because the enclosure case of the shock measurement apparatus according to the present invention has the same size as a disk drive device, the shock measurement apparatus can measure shock while attached to a region in the computer that is intended for installation of a disk drive device, the media bay of a notebook PC. This means that shock can be measured without altering the physical characteristics of the computer under measurement. Therefore, the shock that would actually be received by the disk drive unit can be precisely measured in an imitative manner. That the enclosure case of the shock measurement apparatus has the same size as a hard disk drive device does not require an exact physical match. In the case of a hard disk drive, it only requires that the shock measurement apparatus can be attached to the media bay as though it were a hard disk drive. The size specification merely requires that the device satisfy requirements regarding attachment position and the connection of the connector, and that the physical characteristics of the computer are not substantially changed. Furthermore, the xe2x80x9chard disk drive devicexe2x80x9d herein is not limited to a hard disk drive. For example, a compact disk (CD) drive and magneto-optical (MO) disk drive may also be attached, like the hard disk drive, to the media bay and are covered by the present invention.
The shock measurement apparatus according to the present invention is supplied with its electric power through the power connector. This arrangement does not require a power supply buttery, thus achieving a shock measurement apparatus that satisfies the requirements of the form factor size, particularly a thickness of 9.5 mm, of the 2.5-inch hard disk drive mounted on a current notebook PC. A shock measurement apparatus of a size equal to or smaller than the form factor size of a 2.5-inch hard disk drive can be achieved because it is supplied with power from the external power supply instead of containing an internal battery.
The shock measurement apparatus according to the present invention includes a sensor for detecting shock. The sensor may be a conventional sensor. For example, a piezoelectric material such as the piezoelectric polymer film described in Published Unexamined Patent Application No. 5-133974, mentioned above, may be used. Acceleration (G: acceleration of gravity) may be measured as the shock value.
One needs to consider where the sensor should be positioned. When the shock measurement apparatus attached to a computer is used for a shock test, directly measuring shock received by the computer would lead to a precise shock measurement. To achieve this, it is desirable that the shock measurement apparatus be placed in a high-stiffness position in the enclosure. The hard disk drive is typically bolted to the notebook PC. The bolted part of the hard disk drive, called a xe2x80x9cfootxe2x80x9d, has high stiffness and directly receives the shock received by the notebook PC. Therefore, it is desirable that parts equivalent to the xe2x80x9cfootxe2x80x9d be provided on the enclosure of the shock measurement apparatus used for measurement of shock to a hard disk drive, and that the sensor is positioned near the foot.
Memory, which can store the results of measurement, is provided in the shock measurement apparatus of the present invention, and the results can be read from the memory. The read results of the measurement can then be reflected in the revisions to the design of a computer.
While the present invention has been described as a shock measurement apparatus, the invention may be applied to other equipment. The present invention provides a shock measurement apparatus for measuring shock received by a variety of equipment. It includes a detachable unit with a power supply connector for providing power to the apparatus. The shock measurement apparatus includes: a shock measurement circuit with a sensor portion for detecting shock, a power connector connected to the power supply connector of the equipment for receiving power for driving the shock measurement circuit. The shock measurement apparatus is attached to a region of the equipment where conventional equipment would be attached.
The shock measurement apparatus according to the present invention is used for shock measurement with the apparatus attached to the region where conventional equipment would be attached. Thus the measured shock value will precisely represent the shock that would be received by conventional equipment attached to the computer.
To attach the shock measurement apparatus to the region where conventional equipment would be attached, the size of the shock measurement apparatus should match the size of conventional equipment. This is because the physical characteristics of the equipment to which the shock measurement apparatus is attached should be the same as the physical characteristics of the equipment to which the conventional equipment is attached. The region to which the conventional equipment is attached is generally a void space. In addition, the apparatus includes fasteners such as bolts for attachment. Therefore, if the shock measurement apparatus is larger than the region, it cannot be attached to the equipment. On the other hand, if the shock measurement apparatus is smaller than the region, it can be placed in the region but cannot be properly attached to the equipment with the fasteners.
It is desirable that the sensors in the shock measurement apparatus of the present invention detect shock in each of X, Y, and Z directions. The shock measurement values in three directions thus obtained can be effectively used for the design of computers or hard drives in order to improve their shock resistance.
The shock measurement circuit in the shock measurement apparatus comprises a central processing unit (CPU) responsible for the operation of the shock measurement circuit, memory for storing measured shock values, and a charge amplifier mounted on a substrate. The shock measurement apparatus of the present invention comprises a minimum set of components required for measuring and recording the shock values. The shock measurement apparatus does not require connections, such as external wiring, when shock is applied to the equipment with the apparatus attached.
By providing, in the shock measurement circuit, an interface for sending/receiving data to and from external devices, data on recorded shock values can be transferred to data collection and analyzing devices such as PCs. The interface may include conventional interface means such as RS232C or USB connections.
The shock measurement apparatus of the present invention applies to a hard disk drive unit or other conventional equipment, which comprises dynamic mechanics, including driving means such as a motor and mechanical elements driven by the driving means, because such a dynamic mechanism is subject to breakage by shock. While a hard disk drive with a dynamic mechanism is a good example of a unit suitable for application of the shock measurement apparatus of the present invention, this does not limit the application of the present invention.
A typical application of the shock measurement apparatus of the present invention is a hard disk drive. Therefore, the shock measurement apparatus of the present invention is a shock measurement apparatus for imitatively measuring shock received by a mobile computer having a region for receiving a hard disk drive, wherein the shock measurement apparatus comprises: an enclosure having the same size as the form factor of a hard disk drive, a shock measurement circuit, which is placed in the enclosure and includes an acceleration sensor for detecting acceleration as shock, and a power receiving connector for receiving power from the internal power supply of the mobile computer. The shock measurement apparatus of the present invention is used for measurement during attachment to the region in which the hard disk drive is to be attached. Thus, although the measured results are imitative of the shock measurement of a computer with a hard disk drive attached, they are highly precise. The results can be effectively reflected in the design of a mobile computer. The attachment region is called a media bay (or device bay).
The shock measurement apparatus of the present invention has a size matching the form factor of a hard disk drive and is used for shock measurement during attachment to a media bay intended for receiving a hard disk drive. The shock measurement apparatus of the present invention, when attached to a notebook PC, allows a precise measurement of shock received by a hard disk drive.
As mentioned above, the form factor of a 2.5-inch hard disk drive installed in widely-used notebook PCs is 100.2xc2x10.25 mm (l) 69.85xc2x10.25 mm (w) 9.5xc2x10.2 mm (h). Accordingly, the shock measurement apparatus of the present invention takes these dimensions. Any shock measurement apparatus having a size within this dimension range is assumed to match the form factor of a 2.5-inch hard disk drive. The physical size of the shock measurement apparatus is not required to be made to exactly match these values. Differences within the form factor specification are allowed. For the shock measurement apparatus of the present invention to allow for shock measurement with higher precision, it should have the same weight as the hard disk drive.
The present invention provides a shock measurement method using the shock measurement apparatus of the present invention for imitatively measuring shock received by a computer or other equipment having a hard disk drive to be detachably attached thereto, comprising the steps of: providing a shock measurement apparatus which comprises a shock measurement circuit including a sensor section for detecting shock and recording means and is used for the shock measurement in such a manner that the shock measurement apparatus is attached to a region intended to be used for the attachment of a hard disk drive unit; setting a parameter for the shock measurement in the shock measurement circuit while the shock measurement apparatus is connected to a controlling computer; attaching the shock measurement apparatus to the region intended to be used for the attachment of the unit with the shock measurement apparatus being disconnected from the controlling computer; and applying shock to said equipment while supplying electric power to the shock measurement apparatus from the equipment to record data on the shock on the recording means.
After the data is recorded, the measurement apparatus is removed from the equipment. Then the data on the shock recorded on the recording means is read into the controlling computer. The read data can be analyzed by the controlling computer.
The shock measurement method of the present invention is used with the shock measurement apparatus attached to the region intended for receiving the hard disk drive. Although the measurement is imitative, shock which would actually be received by the unit can be precisely represented. Because the shock measurement apparatus is supplied with electric power from the computer or other equipment, the shock measurement apparatus does not require a power supply battery. Accordingly, the size of the shock measurement apparatus can be reduced.
Once the parameters for shock measurement are set from the external controlling computer, the wiring connection with the controlling computer can be removed. The wiring does not hinder the application of shock.